Assessing the inhalation cancer risk of particulate matter bound polycyclic aromatic hydrocarbons (PAHs) for the elderly in a retirement community of a mega city in North China

Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is limited by the lack of environmental exposure data among different subpopulations. To assess the exposure cancer risk of particulate carcinogenic polycyclic aromatic hydrocarbon pollution for the elderly, this study conducted a personal exposure measurement campaign for particulate PAHs in a community of Tianjin, a city in northern China. Personal exposure samples were collected from the elderly in non-heating (August–September, 2009) and heating periods (November–December, 2009), and 12 PAHs individuals were analyzed for risk estimation. Questionnaire and time-activity log were also recorded for each person. The probabilistic risk assessment model was integrated with Toxic Equivalent Factors (TEFs). Considering that the estimation of the applied dose for a given air pollutant is dependent on the inhalation rate, the inhalation rate from both EPA exposure factor book was applied to calculate the carcinogenic risk in this study. Monte Carlo simulation was used as a probabilistic risk assessment model, and risk simulation results indicated that the inhalation-ILCR values for both male and female subjects followed a lognormal distribution with a mean of 4.81?×?10^?6 and 4.57?×?10^?6, respectively. Furthermore, the 95 % probability lung cancer risks were greater than the USEPA acceptable level of 10^?6 for both men and women through the inhalation route, revealing that exposure to PAHs posed an unacceptable potential cancer risk for the elderly in this study. As a result, some measures should be taken to reduce PAHs pollution and the exposure level to decrease the cancer risk for the general population, especially for the elderly.     

环境基础设施市场化运作下的政府管理

论述了环境基础设施投资运行机制的市场化改革，是解决目前环境基础设施供需矛盾尖锐、投入不足、效率低下的一条重要途径。认为环境基础设施的特殊性决定了其在市场化运作中，政府加强管理具有重要意义。结合城市给排水和垃圾处理设施的特点，提出并讨论了在市场化运作的背景下，政府管理城市环境基础设施的主要目标、内容及政策体系。     

光塑性在连续挤压成形研究中的若干关键技术

分析了光塑性和连续挤压技术的特点,总结了光塑性在连续挤压成形研究中的若干关键技术,重点研究了连续挤压过程的光塑性实验建模、光塑性材料的选取、试样制取过程中存在的问题,为今后本领域工作的开展指出可能涉及到的问题.     

Eco-environment contribution of agroforestry to agriculture development in the plain area of China—Huai''''an Prefecture, Jiangsu Province as the case study area

IntroductionSincethe 195 0s ,manyforestshavebeenplantedintheplainareasofChinafortheimprovementoftheenvironmentalqualityandensuringthesupplyofwoodandnon timberforestproducts.Forestrydevelopmenthasplayedanimportantroleinadjustingtheruraleconomicstructure ,i…     

Collective decision through self-assembling

The ant genus Oecophylla is well known for forming chains that allow a gap to be bridged. Using a set-up where the ants are given the choice of building a chain on two identical sites, we show that they always end up focusing their activity on a single one. A mathematical model suggests that this result depends on probabilities of entering and leaving the chain that depend on its size. The same model allows some predictions to be made on the influence of the nest size. Thus, a critical population size is needed in order to observe the formation of at least one chain. Over this size we observe the transitory coexistence of two chains, for which the duration is positively correlated to the nest size. However, this coexistence always leads to the formation of one chain and to the break-up of the other one. Following on from these results we give similar examples in gregarious arthropods and discuss the possibility of these mechanisms being generic for a wide range of collective activities and decisions.     

排污权交易与我国环境法治进程

排污许可证制度、排污收费制度和排污权交易制度对于环境污染的治理能够发挥出无可替代的作用.作为三种不同性质的治污手段,其运行机制有本质上的区别,也使得其实施的过程以及效用存在质的差别.本文通过对此三种治污手段的比较,意在揭示政府管制与市场调节两种不同的治理机制对我国环境法治进程的影响,并初步探讨了我国环境法治进程的路径选择.     

酿酒酵母吸附Zn(Ⅱ)过程中阳离子(K+,Mg2+,Na+,Ca2+)的变化分析

研究了酿酒酵母无缓冲溶液体系吸附Zn(Ⅱ)的过程中各种阳离子的变化情况.研究结果表明,当Zn(Ⅱ)的初始浓度是0.08～0.8 mmol·L-1,酵母浓度约1 g·L-1,初始pH为5.65,反应38h内,酵母的Zn(Ⅱ)吸附量为74.8～654.8μmol·g-1,去除率达到76.4%～92.8%,pH值升高0.55～1.28.吸附过程中酵母首先快速释放大量K ,其次是Mg2 和Na ,Ca2 的释放量较少,数量级一般可分别达到几百、几十和几个μmol·g-1.以离子交换为基础计算的各阳离子释放量总和一般超过Zn(Ⅱ)的吸附量,证明酵母吸附Zn(Ⅱ)的机理之一是离子交换,但不唯一.无缓冲溶液体系酵母吸附Zn(Ⅱ)的过程中溶液pH值升高,H 被吸收,K 等阳离子释放,是生物体细胞的本质属性,与Zn(Ⅱ)是否存在无关,但是Zn(Ⅱ)可以促进阳离子的释放以及降低酵母对H 的吸收,也反映出Zn(Ⅱ)与H 之间可以竞争细胞表面吸附位.死酵母的吸附量低于未处理酵母,与阳离子交换能力关系不大,可能与细胞表面变形导致Zn(Ⅱ)吸附困难有关.     

污水土地处理系统ORP变化特征与COD去除率关系的试验研究

污水土地处理技术具有投资少,运行费用低,处理效果好,以及可实现污水处理的无害化、资源化等特点。用污水土地处理系统来处理生活污水,氧化还原环境是一个重要影响因素,而氧化还原电位的高低可以反映系统氧化水平的高低。本论文设计了一个带有多个通气孔的毛管逆滤渗污水处理装置,并用于处理生活污水。试验按照打开通气孔数量的不同被分为全封闭、半封闭（打开8个）和全打开（打开16个）三组同时进行,探讨开启不同数量通气孔时系统内外柱氧化还原电位（ORP）的变化情况以及ORP与系统COD去除率之间的关系,从而为更科学地设计和控制污水处理系统提供依据。试验结果表明：ORP的变化与系统通气性和COD去除率密切相关;系统通气性越好,COD去除率越高。     

初始压力对连通容器甲烷-空气混合物泄爆压力的影响

建立球形容器与管道、2个球形容器与管道组成的2种形式的连通容器试验装置,研究初始压力对连通容器甲烷-空气混合物泄爆压力的影响。结果表明:连通容器内泄爆超压随初始压力增加而增大,并与初始压力近似成线性关系;对于2个球形容器与管道组成的连通容器,起爆容器的泄爆超压始终小于传爆容器;泄爆方式和点火方式对连通容器泄爆超压有较大影响,大容器点火时,2个容器的泄爆压力差随初始压力增加而增大,但小容器点火时,2个容器的泄爆压力差随初始压力的增加变化较小;初始压力对不同结构和尺寸的连通容器的泄爆压力的影响不同,当令初始压力对大容器点火时,小容器内泄爆压力受影响最大,而当对单球形容器与管道组成的连通容器的小容器点火时,小容器内泄爆压力受影响最小。     

骨炭粉对Cd污染农田的修复效果与稳定性评价

为了探明骨炭粉对Cd污染土壤的修复效果及稳定性,以潮土与红壤Cd污染农田土壤为对象,基于土壤Cd有效态、作物降Cd率（DR,%）及降Cd失活率（IR,%）等指标,研究田间条件下施用3种浓度（0.25%、0.50%及1.0%）骨炭粉对Cd污染土壤的修复效果及120,360d后修复效果的稳定性.结果表明：骨炭粉处理均能有效促进潮土与红壤中作物生长,增加作物产量.施用骨炭粉能不同程度提高土壤中pH值、阳离子交换量（CEC）、全磷及有效磷含量;其中,0.5%和1.0%骨炭粉处理均显著（P<0.05）提高土壤pH值、土壤全磷及有效磷含量.与对照相比,不同骨炭粉处理120d后潮土和红壤中有效态Cd含量分别降低32.1%~48.4%、32.8%~56.2%,360d后土壤中有效态Cd仍然显著低于对照,降幅为26.9%~37.8%、25.8%~39.5%.对修复后三季作物Cd吸收测定结果表明,与对照相比,不同浓度（0.25%~1.0%）骨炭粉处理的第一季作物降Cd率（DR_-Cd）分别达36.0%~60.4%、33.9%~58.2%,作物降Cd率随骨炭粉施用量增加而增加.基于降Cd失活率（IR_-Cd）对骨炭粉修复效果的稳定性测定结果表明,潮土与红壤施用骨炭粉360d后,第三季作物降Cd失活率IR_-Cd为21.2%~34.7%和6.2%~21.6%,表明在酸性红壤中修复效果的稳定性大于潮土.综上骨炭粉对Cd污染土壤的修复效果及其稳定性结果表明,骨炭粉在Cd污染农田土壤修复中具有较大应用价值.